Mom, 39, loses battle with cancer after she pens heartbreaking letter to her ...

A mother whose battle with cancer went public after her scathing letter to the insurer that refused to cover her treatment has died.

Erika Zak, 39, died early Friday after she developed complications during surgery at the Cleveland Clinic in Ohio, her husband Scott Powers confirmed to the Daily News.

Her death came after she spent the last five years battling colon cancer that spread to her liver.

Only a liver transplant might have saved her but her insurance company had refused to pay for the treatment.

'The stars briefly aligned while we were at the hospital for an unrelated medical procedure and an organ miraculously became available right then for transplant. We were so excited and rushed our daughter to spend a half hour with Erika,' the family said in a released statement.

'She then quickly went into the OR, but deep into the surgery, her body couldn't handle some of the trauma apparently. She died in surgery.'

Erika's story drew national attention after her insurance provider denied her coverage for the transplant.

Scott Powers (left) and his wife Erika Zac (right) have been fighting to get her a liver transplant to save Erika's life from the cancer she had been battling since their daughter, Loïe was born

The insurer called the surgery an 'unproven' treatment - despite a letter from Erika's doctors insisting that it was not only a valid course of action, but the only shot she would have at survival.

Erika fought back the denials, watching her body fall apart as her liver failed, she told CNN.

Finally, her third and most scathing letter to UnitedHealthcare changed the company's mind.

The procedure was approved after she wrote UnitedHealth Group's CEO David Wichmann to let him now about the 'shockingly incompetent manner' in which the insurer handled her case.

'Given that my life hangs in the balance...,' she wrote in the April 2018 letter, 'it is unconscionable it has not been undertaken with the level of competence and professionalism anyone would expect of UHC.'

With the prospects of a new liver, Erika thought she had chance at seeing her daughter grow up.

Erika had had only a few healthy months with her girl, Loïe.

Shortly after Loïe was born five years ago, Erika was diagnosed with stage 4 metastatic colon cancer.

Erika was only 34, fighting cancer for the second time in her life and suddenly unsure if she would even live to see her daughter's first birthday.

Tumors were surgically removed from her colon, and she began chemo treatments.

But disaster struck during microwave ablation surgery that targeted the cancer that had spread to Erika's liver.

The procedure is supposed to use heat to precisely attack the tumors but something went wrong and a fist-sized hole was cut into Erika's already-damaged liver. Her bile ducts were ruined, too.

Due to the damage to her liver, she developed dilated blood vessels that frequently bled.

Every sign of bleeding or fever was cause for panic in the Zak household.

Her doctors worried constantly that any infection would kill Erika.

Erika was beautiful, but you could see that she was sick. Her green eyes were ringed with yellow - jaundice, a common symptom of liver failure.

Bile drained into ostomy bags outside Erika's scarred abdomen. Most of her liver was already dead, and she had lost atleast 20lbs.

In a last ditch attempt to stop Erika's cancer two years ago, she was given an experimental immunotherapy, which worked wonders for her.

Every three weeks, Erika traveled to the hospital her her home in Portland, Oregon for the treatment.

She could survive the cancer, but her liver was expected to only get worse.

All 100 physicians that have treated Erika echoed the same thing: They didn't know when, but without a new liver, she would die.

For the first time in five years, Erika would have a fighting chance, if she got the new liver.

She and her husband, Scott, met with a Cleveland Clinic transplant team for evaluations.

Erika had been in the hospital multiple times due to complications of a surgery to remove tumors from her live that the 39-year-old mother had in 2014

At the beginning of February 2018, she was given the go-ahead from the doctors. They put her on the waiting list for a liver.

The family's elation didn't last long. Their health insurance company declined to cover the transplant.

UnitedHealthcare, the nation's largest insurance company, claimed that a liver transplant was not a 'promising'